They perform better than non-vegans as e.g. extreme athletes, olympians, body builders and marathon runners - many world record holders in sports.
Veggies are far cheaper in India than milk products, I have been there. Also you're grasping for excuses, take a look at the market, what you say is simply not true even here in Sweden.
A bad diet is bad and dangerous regardless of your ethical stances. There are meat-eaters living off of fast food. Also the general idea of veganism being hard and dangerous is yet another wilful delusion, a piece in the puzzle to keep you from having any cognitive dissonance, it's a rare occurence and it's not hard to eat right and well. In fact it's far easier to eat nutritionally right and well as a vegan, considering the far-reaching negative effects of milk-products and meat.
Speak for yourself man. There is no inherent faculty that drives you to need or strive for eating innocent animals like some troglodyte. Have a look at the list of some of the most accomplished people in history that didn't eat meat.
Ethics are subjective, and if you were to take a stance for enslavement of generations of entire species, torment, emotional and physical violations and finally murder, and not call it barbaric then that will have to stand for you as, but you're not alone in defending various heinous practices on this planet, but few evils are so willingly ignored by the weak and the avaricious as eating animals and everything that comes that.